doc.: ieee 802.22-06/0084-02-0000 submission june 2006 jianwei zhang, huawei slide 1 mac management...
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doc.: IEEE 802.22-06/0084-02-0000
Slide 1Submission
June 2006
Jianwei Zhang, Huawei
MAC Management Message for Efficient SensingWith Supplements on Pages 17 – 22 (June 08)With Supplements on Pages 17 – 22 (June 08)
IEEE P802.22 Wireless RANs Date: 2006-06-01
Notice: This document has been prepared to assist IEEE 802.22. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
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Authors:Name Company Address Phone email
Vincent K. N. Lau HKUST Hong Kong, China 852-2358-7066 [email protected]
Roger S. Cheng HKUST Hong Kong, China 852-2358-7072 [email protected]
Ross D. Murch HKUST Hong Kong, China 852-2358-7044 [email protected]
Wai Ho Mow HKUST Hong Kong, China 852-2358-7070 [email protected]
Khaled Ben Letaief HKUST Hong Kong, China 852-2358-7064 [email protected]
Linjun Lu Huawei Technologies Shenzhen, China 0086-755-28973119 [email protected]
Soo-Young Chang Huawei Technologies Davis, CA, U.S. 1-916 278 6568 [email protected]
Jianwei Zhang Huawei Technologies Shanghai, China 86-21-68644808 [email protected]
Lai Qian Huawei Technologies Shenzhen, China 86-755-28973118 [email protected]
Jianhuan Wen Huawei Technologies Shenzhen, China 86-755-28973121 [email protected]
doc.: IEEE 802.22-06/0084-02-0000
Slide 2Submission
June 2006
Jianwei Zhang, Huawei
Co-Authors:
Name Company Address Phone email
Edward K. S. Au HKUST Hong Kong, China 852-2358-7086 [email protected]
Peter W. C. Chan HKUST Hong Kong, China 852-2358-7086 [email protected]
Ernest S. Lo HKUST Hong Kong, China 852-2358-7086 [email protected]
Lingfan Weng HKUST Hong Kong, China 852-2358-7086 [email protected]
Zhou Wu Huawei Technologies Shenzhen, China 86-755-28979499 [email protected]
Jun Rong Huawei Technologies Shenzhen, China 86-755-28979499 [email protected]
Jian Jiao Huawei Technologies Beijing, China 86-10-82882751 [email protected]
Mingwei Jie Huawei Technologies Shenzhen, China 86-755-28972660 [email protected]
doc.: IEEE 802.22-06/0084-02-0000
Slide 3Submission
June 2006
Jianwei Zhang, Huawei
MAC Management Messages MAC Management Messages for Efficient Sensingfor Efficient Sensing
doc.: IEEE 802.22-06/0084-02-0000
Slide 4Submission
June 2006
Jianwei Zhang, Huawei
OutlineOutlineMotivation:
• WRAN: limited resource for sensing
• More sensing resource (sensing period and number of sensing CPEs) should be allocated to “urgent” channels
• To facilitate this, BS needs to specify discontiguous channels for CPE to sense
Three parts:
I. The need to specify the discontiguous channels (Why “urgent”?) • What do we mean by “urgent”
• Why some channels are more “urgent” than the others
• Why those “urgent” channels can be discontiguous
II. The proposed changes to existing MAC messages (“Channel list”)
III. Simulation results
doc.: IEEE 802.22-06/0084-02-0000
Slide 5Submission
June 2006
Jianwei Zhang, Huawei
Why “urgent”? --- example 1Why “urgent”? --- example 1
• What are “urgent” channels?– “Urgent” channels are those that requires
considerably more resources to perform reliable sensing
– Some channels are more “urgent” than others since the density of CPEs is not uniform in the cell. Some region requires more resource to detect incumbents
– E.g.: Incumbent detection at proximity of CPE1 is more difficult due to low local CPE-density.
– Since Channel A is being used by CPE1 but CPE1 alone is not efficient enough to sense the Channel A reliably, it is more urgent than Channels B and C.
doc.: IEEE 802.22-06/0084-02-0000
Slide 6Submission
June 2006
Jianwei Zhang, Huawei
Why “urgent”? --- example 1Why “urgent”? --- example 1
• What if insufficient resource is allocated to sensing Channel A?
– Either the detection capability of incumbent presence is unsatisfactory, or
– System false alarm rate is too high
– E.g. One system false alarm leads to 10 minutes prohibited use of Channel A.
Pdec = 0.9, Pfalse = 0.1, Tdetect = 2sec
false alarm per minute
= (1-0.9^(60/2)) = 96%
a false alarm will trigger 10-minutes Non-Occupation Period.
Channel can hardly be used.
doc.: IEEE 802.22-06/0084-02-0000
Slide 7Submission
June 2006
Jianwei Zhang, Huawei
Why “urgent”? --- example 1Why “urgent”? --- example 1
• Solution:– Allocate more CPEs to spend
more periods sensing urgent channels. (e.g. assign CPE 2-4 to help CPE 1 to sense Ch A)
• Urgent channels change dynamically and generally will not appear contiguous.
• The BS needs to have efficient mechanism to specify discontiguous channels for CPEs to sense.
doc.: IEEE 802.22-06/0084-02-0000
Slide 8Submission
June 2006
Jianwei Zhang, Huawei
Why “urgent”? --- example 2Why “urgent”? --- example 2
• Channels 3, 4, and 5 are less “urgent”, probably due to
– TV signals present (database or site survey)
– Temporarily strong incumbent signal (e.g. TV station’s remote -news van)
• Difference between “channel aggregation”
– CPE shall not only sense the channels it is using, but need to sense channels used by some other (but may not be all) CPEs and channels not used by the cell.
doc.: IEEE 802.22-06/0084-02-0000
Slide 9Submission
June 2006
Jianwei Zhang, Huawei
• A flexible and efficient sensing scheme is needed for BS to specify discontiguous channels for the CPEs to sense.
• The current spec imposes a severe overhead punishment on the deployment of such schemes.
doc.: IEEE 802.22-06/0084-02-0000
Slide 10Submission
June 2006
Jianwei Zhang, Huawei
Proposed changes --- “channel list”Proposed changes --- “channel list”
Current Bulk Measurement Request
Syntax Size
BLM-REQ_Message_Format() {
Management Message Type = 39 8 bits
Transaction ID 16 bits
Starting Channel Number 8 bits
Number of Channels 8 bits
Confirmation Needed 1 bit
Number of Single Measurement Requests
3 bits
Single Measurement Requests Variable
}
Proposed Bulk Measurement Request
Syntax Size
BLM-REQ_Message_Format() {
Management Message Type = 39 8 bits
Transaction ID 16 bits
Interval-basis Channel List Variable
Confirmation Needed 1 bit
Number of Single Measurement Requests
3 bits
Single Measurement Requests Variable
}
doc.: IEEE 802.22-06/0084-02-0000
Slide 11Submission
June 2006
Jianwei Zhang, Huawei
Proposed changes --- “channel list”Proposed changes --- “channel list”
Syntax Size Notes
Interval_basis_Channel_List_Format() {
Starting Channel Number 8 bits The index of the starting channel
Number of Channels 8 bits The number of channels in the current interval
Linker 1 bit 1: The next 17 bits follow the interval-basis structure0: The Channel List structure is terminated here
}
Interleaved-based channel list*
* The Beacon Measurement Report and Consolidated Spectrum Occupancy Measurement Report should also be changed accordingly, please refer to our report for the details.
Same as original schemeOnly one bit overhead is
added even if the channel is contiguous
doc.: IEEE 802.22-06/0084-02-0000
Slide 12Submission
June 2006
Jianwei Zhang, Huawei
Simulation resultSimulation result
Required BLM_REQ Overhead (Location Config Measurement)
0
200
400
600
800
1000
1200
1400
0 5 10 15
Number of channel intervals
Ove
rhea
d (
bit
s)
Current Spec
HuaWei's Channel List
doc.: IEEE 802.22-06/0084-02-0000
Slide 13Submission
June 2006
Jianwei Zhang, Huawei
Simulation resultSimulation result
Required BML_REQ Overhead (Beacon Measurement)
0
500
1000
1500
2000
2500
0 5 10 15
Number of channel intervals
Ove
rhea
d (
bit
s)
Current Spec
HuaWei's Channel List
doc.: IEEE 802.22-06/0084-02-0000
Slide 14Submission
June 2006
Jianwei Zhang, Huawei
Simulation resultSimulation result
Required BLM_REQ Overhead (TV Measurement)
0
200
400
600
800
1000
1200
1400
1600
1800
0 5 10 15
Number of channel intervals
Ove
rhea
d (
bit
s)
Current Spec
HuaWei's Channel List
doc.: IEEE 802.22-06/0084-02-0000
Slide 15Submission
June 2006
Jianwei Zhang, Huawei
Simulation resultSimulation result
Required CSOMR Overhead (Assume 40 channels)
0
100
200
300
400
500
600
0 5 10 15
Number of channel intervals
Ove
rhea
d (
bit
s)
Current Spec
HuaWei's Channel List
doc.: IEEE 802.22-06/0084-02-0000
Slide 16Submission
June 2006
Jianwei Zhang, Huawei
ConclusionConclusion
• We have proposed a flexible and efficient “channel list” structure to reduce the overhead for the BS to specifies discontiguous channels for CPEs to sense.
• Significant overhead savings have been shown through the numerical results.
doc.: IEEE 802.22-06/0084-02-0000
Slide 17Submission
June 2006
Jianwei Zhang, Huawei
• As per our proposal(a) an one-bit overheadone-bit overhead when only contiguousonly contiguous channels are sensed;
(b) save hundred of bitssave hundred of bits when discontiguousdiscontiguous channels are sensed.
• An Example Scenario of Discontiguous Channels[1] CPEs need to do in-band sensing;
[2] BS holds a backup channel list and it askes CPEs to sense these channels
[3] In order to avoid adjacent channel interference, the channels in the backup list should be as far away from the current channel as possible (this is mentioned in page 167 of Draft v0.1)
It is very possible that CPEs need to sense discontiguous channels
Supplement: Summary & ExampleSupplement: Summary & Example
doc.: IEEE 802.22-06/0084-02-0000
Slide 18Submission
June 2006
Jianwei Zhang, Huawei
Supplement: Comments & Technical DifficultiesSupplement: Comments & Technical Difficulties
• Comments: Simulations should be performed to figure out how often (a)
and (b) appear in WRAN systems.
• Technical DifficultiesTechnical Difficulties
It is almost not possible to simulate how likelyhow likely a system will have
discontiguous channels for sensing. It is because it depends on
deployment, probability distributiondeployment, probability distribution that the number of discontiguous
channels occur, and the like.
Given a particular sensing list of discontiguous channels, there are a lot of
implementation-specific / vendor-dependent issuesimplementation-specific / vendor-dependent issues that are not well-
defined, such as sensing scheduling, sensing algorithmsensing scheduling, sensing algorithm, and the like.
Our concern is how we can figure out our conjecture / guess on some
parameters such that all members can feel that these make sense.
doc.: IEEE 802.22-06/0084-02-0000
Slide 19Submission
June 2006
Jianwei Zhang, Huawei
• Simulations are performed based on our example scenario.
• Consolidated Spectrum Occupancy Measurement Report (CSOMR):
– Periodic Transmit from CPE to BS, we shall study the average overhead per transmission.
• Beacon Measurement Request :
– May not need periodic transmission, event driven instead. When some incumbents appear in the
sensing channels, BLM_REQ is transmitted.
• Assumptions:– Suppose CPE can sense N channels (CPE Sensing Capability): one in-band sensing and (N-1) out-
band sensing channels selected from backup channels
– TV channels are randomly distributed
– Part 74 incumbents appear with a probability P in each channel
– The CPE report once 2 seconds
– The BS sends the BLM_REQ when any of the reported sensing channels is blocked
– Presence state of Part 74 incumbents in each channel slowly changes: the probability of an incumbent user detected in the channel which is clean in last report is P_chg.
Supplement: Simulation SettingsSupplement: Simulation Settings
doc.: IEEE 802.22-06/0084-02-0000
Slide 20Submission
June 2006
Jianwei Zhang, Huawei
Supplement: Simulation Results – CSOMRSupplement: Simulation Results – CSOMR
10 20 30 40 50 60 70 80 90200
250
300
350
400
450
500
# Channels Occupied by Incumbent
Ove
rhea
d (b
its)
Required CSOMR Overhead (assume 100 channels)
HuaWei Proposed
Current Spec
5 10 15 20 25 30 35 40 45 50200
300
400
500
600
700
800
900
1000
1100
1200
# Channels a CPE Can Sense
Ove
rhea
d (b
its)
Required CSOMR Overhead (assume 100 channels)
HuaWei Proposed
Current Spec
Figure 1
Figure 2
Total Channels: 100
CPE Sensing Capability: 10
Total Channels: 100
Number of channels occupied
by incumbent users on average: 50
doc.: IEEE 802.22-06/0084-02-0000
Slide 21Submission
June 2006
Jianwei Zhang, Huawei
Supplement: Simulation Results – BLM_REQ Supplement: Simulation Results – BLM_REQ (1)(1)
5 10 15 20 25 30 35 40 45 500
500
1000
1500
2000
2500
# Channels a CPE Can Sense
Ove
rhea
d (b
its/s
ec)
Required BLM_REQ Overhead (Beacon Measurement)
HuaWei Proposed
Current Spec
10 20 30 40 50 60 70 80 90100
200
300
400
500
600
700
800
900
# Channels Occupied by TV
Ove
rhea
d (b
its/s
ec)
Required BLM_REQ Overhead (Beacon Measurement)
HuaWei Proposed
Current Spec
Figure 3
Figure 4
Total Channels: 100
CPE Sensing Capability: 10
P_chg: 0.1
Total Channels: 100
Number of channels occupied
by TV stations on average: 50
P_chg: 0.1
doc.: IEEE 802.22-06/0084-02-0000
Slide 22Submission
June 2006
Jianwei Zhang, Huawei
Supplement: Simulation Results – BLM_REQ Supplement: Simulation Results – BLM_REQ (2)(2)
10-4
10-3
10-2
10-1
100
0
100
200
300
400
500
600
700
800
Probabilty that the Sensing Reult of a Channel Changes between 2 Reports
Ove
rhea
d (b
its/s
ec)
Required BLM_REQ Overhead (Beacon Measurement)
HuaWei Proposed
Current Spec
Figure 5
Total Channels: 100
Number of channels occupied
by TV stations on average: 50
CPE Sensing Capability: 10